Moths are related to butterflies, but they're most often active at night instead of day. They use their large antennae to sense, smell, and guide themselves in the dark. Interestingly, the number of moth species is estimated at 160,000, so "moth" is a fairly broad descriptor.

Most commonly found outside of Re-Tail at night when the light is on. If you press A right in front of the sign, it'll make you read the sign. So prepare your net and approach the sign slowly, then aim for the moth!